The use of sprinklers is a common method of irrigating landscape and vegetation areas. In a typical irrigation system, various types of sprinklers are used to distribute water over a desired area, including rotating stream type and fixed spray pattern type sprinklers. One type of irrigation sprinkler is the rotating deflector or so-called micro-stream type having a rotatable vaned deflector for producing a plurality of relatively small water streams swept over a surrounding terrain area to irrigate adjacent vegetation.
Rotating stream sprinklers of the type having a rotatable vaned deflector for producing a plurality of relatively small outwardly projected water streams are known in the art. In such sprinklers, one or more jets of water are generally directed upwardly against a rotatable deflector having a vaned lower surface defining an array of relatively small flow channels extending upwardly and turning radially outwardly with a spiral component of direction. The water jet or jets impinge upon this underside surface of the deflector to fill these curved channels and to rotatably drive the deflector. At the same time, the water is guided by the curved channels for projection outwardly from the sprinkler in the form of a plurality of relatively small water streams to irrigate a surrounding area. As the deflector is rotatably driven by the impinging water, the water streams are swept over the surrounding terrain area, with the range of throw depending on the flow rate of water through the sprinkler.
In rotating stream sprinklers of this general type, it is desirable to control the arcuate area through which the sprinkler distributes water. In this regard, it is desirable to use a sprinkler that distributes water through a variable pattern, such as a full circle, half-circle, or some other arc portion of a circle, at the discretion of the user. Traditional variable arc sprinklers suffer from limitations with respect to setting the water distribution arc. Some have used interchangeable pattern inserts to select from a limited number of water distribution arcs, such as quarter-circle or half-circle. Others have used punch-outs to select a fixed water distribution arc, but once a distribution arc was set by removing some of the punch-outs, the arc could not later be reduced. Many conventional sprinklers have a fixed, dedicated construction that permits only a discrete number of arc patterns and prevents them from being adjusted to any arc pattern desired by the user.
Other conventional sprinkler types allow a variable arc of coverage but only for a limited arcuate range. It would be desirable to have a single sprinkler head that covers substantially a full range of arcuate coverage, rather than several models that provide a limited arcuate range of coverage. For rotating stream sprinklers, however, it is difficult to provide coverage for low angles, such as from about 0 degrees to about 90 degrees, because water flow may not be adequate at these low angles to impart sufficient force to the rotating deflector. Thus, it would be desirable to have a single sprinkler head that could provide arcuate coverage from about at least 90 degrees to about 360 degrees.
Because of the limited adjustability of the water distribution arc, use of such conventional sprinklers may result in overwatering or underwatering of surrounding terrain. This is especially true where multiple sprinklers are used in a predetermined pattern to provide irrigation coverage over extended terrain. In such instances, given the limited flexibility in the types of water distribution arcs available, the use of multiple conventional sprinklers often results in an overlap in the water distribution arcs or in insufficient coverage. Thus, certain portions of the terrain are overwatered, while other portions are not watered at all. Accordingly, there is a need for a variable arc rotating stream sprinkler head that allows a user to set the water distribution arc along the continuum from at least substantially 90 degrees to substantially 360 degrees, without being limited to certain discrete angles of coverage.
It is also desirable to control or regulate the throw radius of the water distributed to the surrounding terrain. In this regard, in the absence of a flow rate adjustment device, the irrigation sprinkler will have limited variability in the throw radius of water distributed from the sprinkler, given relatively constant water pressure from a source. The inability to adjust the throw radius results both in the wasteful watering of terrain that does not require irrigation or insufficient watering of terrain that does require irrigation. A flow rate adjustment device is desired to allow flexibility in water distribution and to allow control over the distance water is distributed from the sprinkler, without varying the water pressure from the source. Some designs provide only limited adjustability and, therefore, allow only a limited range over which water may be distributed by the sprinkler.
In addition, it has been found that adjustment of the distribution arc is a commonly used feature of rotating stream sprinklers and other sprinklers. It would be therefore desirable to make this feature accessible from the top of the sprinkler's cap, which is generally more convenient to the user. Conventional rotating stream sprinklers generally do not allow arc adjustment from the top of the sprinkler's cap.
Accordingly, a need exists for a truly variable arc sprinkler that can be adjusted to any water distribution arc from at least about 90 degrees to substantially 360 degrees. In addition, a need exists to increase the adjustability of flow rate and throw radius of an irrigation sprinkler without varying the water pressure, particularly for rotating stream sprinkler heads of the type for sweeping a plurality of relatively small water streams over a surrounding terrain area. Further, a need exists for a rotating stream sprinkler that allows a user to adjust the distribution arc from the top of the sprinkler's cap and to adjust the throw radius by actuating or rotating an outer wall portion of the sprinkler.